CVE-2026-42012

Gnutls: gnutls: certificate validation bypass due to improper handling of uri and srv sans

CVSS score

7.1

EPSS probability

%0.5

Risk score

0.0

Published

4 mo ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

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Vulnerability description

DayBreach CVE AI Research

CVE-2026-42012 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted certificate that contains Uniform Resource Identifier (URI) or Service (SRV) Subject Alternative Names (SANs). This could cause the certificate validation process to incorrectly fall back to checking DNS hostnames against the Common Name (CN), potentially allowing the attacker to spoof legitimate services or intercept sensitive information.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-42012 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	redhat	gnutls	View
2	Red Hat	Red Hat Enterprise Linux 10	View
3	Red Hat	Red Hat Enterprise Linux 10.0 Extended Update Support	View
4	Red Hat	Red Hat Enterprise Linux 7 Extended Lifecycle Support	View
5	Red Hat	Red Hat Enterprise Linux 8	View
6	Red Hat	Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	View
7	Red Hat	Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support	View
8	Red Hat	Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	View
9	Red Hat	Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On	View
10	Red Hat	Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	View
11	Red Hat	Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support	View
12	Red Hat	Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On	View
13	Red Hat	Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On	View
14	Red Hat	Red Hat Enterprise Linux 8.8 Telecommunications Update Service	View
15	Red Hat	Red Hat Enterprise Linux 8.8 Telecommunications Update Service	View
16	Red Hat	Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions	View
17	Red Hat	Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions	View
18	Red Hat	Red Hat Enterprise Linux 9	View
19	Red Hat	Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions	View
20	Red Hat	Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions	View
21	Red Hat	Red Hat Enterprise Linux 9.6 Extended Update Support	View
22	Red Hat	Cert Manager support for Red Hat OpenShift release 1.17	View
23	Red Hat	Cert Manager support for Red Hat OpenShift release 1.17	View
24	Red Hat	Cert Manager support for Red Hat OpenShift release 1.17	View
25	Red Hat	Cert Manager support for Red Hat OpenShift release 1.17	View
26	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
27	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
28	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
29	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
30	Red Hat	Cert Manager support for Red Hat OpenShift release 1.18	View
31	Red Hat	Cert Manager support for Red Hat OpenShift release 1.20	View
32	Red Hat	Red Hat Discovery 2	View
33	Red Hat	Red Hat Discovery 2	View
34	Red Hat	Red Hat Hardened Images	View
35	Red Hat	Red Hat OpenShift AI 3.4	View
36	Red Hat	Red Hat Update Infrastructure 5	View
37	Red Hat	Red Hat Update Infrastructure 5	View
38	Red Hat	Red Hat Update Infrastructure 5	View
39	Red Hat	Red Hat Update Infrastructure 5	View
40	Red Hat	Red Hat Update Infrastructure 5	View
41	Red Hat	Red Hat Update Infrastructure 5	View
42	Red Hat	Red Hat Update Infrastructure 5	View
43	Red Hat	Red Hat Enterprise Linux 6	View
44	Red Hat	Red Hat OpenShift Container Platform 4	View

Total affected vendors: 2|Products: 44

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
7.1	CVSS V31	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N	NVD
7.1	CVSS 3.x	—	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N	Microsoft MSRC
7.1	CVSS V3_1	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N	CVE CNA

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

reference

Yama veya çözüm referansı

Open source

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Apply the official update named in the evidence only to the matching product and version.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-42012 is associated with the following CWEs:

CWE-295: Common Weakness Enumeration Entry CWE-295

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-42012 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

UserGerekiyor

Official Sources and Advisories

RHSA-2026:13274vendor-advisory RHSA-2026:20611vendor-advisory RHSA-2026:20612vendor-advisory RHSA-2026:20613vendor-advisory RHSA-2026:26319vendor-advisory RHSA-2026:26409vendor-advisory RHSA-2026:29197vendor-advisory RHSA-2026:30004vendor-advisory RHSA-2026:30849vendor-advisory RHSA-2026:30850vendor-advisory

CVSS Vector Radar Chart

7.1 / 10

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone required

User Interaction—

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)High

Availability (Erişilebilirlik)None

Yama doğrulandı

1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

redhat

Red Hat

Weakness Type (CWE & CAPEC)

CWE-295

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